Pneumatic jar-ramming molding machine



w. LEWIS 1,763,662

June 17, 1930.

PNEUMATIC JAR RAMMING MOLDING MACHINE 3 Sheets- Sheet 1 Filed June 15,1927 IN VEN TOR wing? v BY W rag FORNEY June 17, 1930. w. LEWIS1,763,662

PNEUMATIC JAR RAMMING MOLDING MACHINE Filed June 15, 1927 3 Sheets-Sheet2 WITNESSES:

a-"4:1 QSQWW June 17, 1930. w. LEWIS 1,763,662

PNEUMATIC JAR RAMMING MOLDING MACHINE Filed June 15, 1927 3 Sheets-Sheet3 coo I O ff w-e g lewdi ATTORNEY.

.7 .40 valve shown in Fig. 2.

Patented June 17, 1930 WiLFRED Lewis, or, navamoee, rennsewiimi enema-mme-eanivnaenbtbise Machine appnaadn ties has '15,

This application is a continuation'in part of my application S. No.141,090 filed 12 October, 1926. g

Objects of the present invention are to prea vent an excessive overrunof thetable; to avoid material variations in the length of the stroke ofthe table; to provide for shifting the jarring valve at veryslowspeeds'so that the exli'aust will always be wide open when it opens atall; to avoid destructive effects in the nature of hammer blows and tocushion the valve stem; to give the exhaust valve a lead in closing soas to retard the table and insure proper contact of the mold with it; toadapt the operation of the machine to and make it equally efiectiveunder diiferent loads imposed by different flasks; and, in the case ofshocklessmachines, to keep the anvil and the table in step. I

Other obj ects of the invention willappear from the'followingdescription and the invention will be claimed at the end of thedescription and the description will begiven with reference to i theaccompanying drawings forming part hereof and illustrating anembodimentof the invention and in which drawings V Figure l'is a sectional viewofa shockless jarring machine embodying all the features of theinvention. 7

, Figure 21s a view oflthe operating valve in section drawn to anenlarged scale showing one of the machine parts to which theimprovements apply. i a

Figure 3 is a view in section on the line MN Fig. 2 showing the airpassages leading from the operating valve to the jarring cylinder.

Figure at is a top view of the operating Figure 5 is a view in crosssection correspohding to Figure 2 showing the piston J in raisedposition with the exhaust valve"D open. 1 y

Figure 6 is a similar view in cross section showing the inlet ports Hclosed owing to the raised postion of the piston J. a 1

In the drawings, 1 is a jarring cylinder having an exhaust valve seat 2.J is a jarring plunger having an airchamber C provided 1ee-"7.' steam.ease.

with an air inlet I and with an'admission" valve seat 0 Bis a hollowvalve body movable in the air chamber O, having twointernal diameters, 6and i, with choke holes, E, inthe wall of 6, at its lowerend. There isprovided at diameter 6 a cylinder space,.an'd ,1, at the A lbWl end ofthe body, B, is an admission v'alve of diameter, 7 to seat upon G K is aspring arranged between the choke sleeve, S, (adapted to seat on ashoulder at the lower end of the casing C) and the valve body B ahdtendingto open the admission valve. B is a bushing of diameters b and 4centered in the valve body and firmly secured thereto. This formsa stopfor the piston V on the valve stem, V, beneath, and acts as a guide forits upper end, V The hollow valve,sten1,V, has three externalcylindrical surfaces, V at the top, of diameter 3, in sliding relationwith the bushing B .V beneath, of diameter '6, moving between stops inthe valve body, and V at the lower end, of diameter 4, bothV and V, arein packed sliding relation with B, and

V is carried downto exhaust. The portion of diameter V constitues apiston element in j the cylinder space at diameter 6. Immediately belowthe piston V for a length about equal to the travel of the valve stem inthe valve body, the diameter 4 is reduced to provide clearance, Y, inWhi'c'h'air' can-be stored a when the piston, V is down against theshoulder on valve body at E, for a, purpose .to be disclosed.vPressur'e' is admitted tothe interior of the valve stem thru ports H,ar-

ranged below the admission valve and carried thru ports, X, in the wallof V into the annularcylinder space above the piston V D is a doublefaced hollow exhaust valve of' which one face, D cooperates with thevalve seat, 2, and of which theother face-,D' ,-coopcrates with theseat, 11, provided in a contractionatthe lower end, V of thestem V.

S is a bypass choke sleeve, sli'dably mounted on the valvesteln at V Itis'tr'aversed on -V in one direction by a "shoulder on the ,3 lower endof the chamber C and in the other directionby the spring, K, under thevalve body, B, and in its highest'position it covers the ports, H. Thediameter of the air inlet, I, is somewhat greater than that of the valvestem V to provide clearance when the latter is raised to open theexhaust. The stops, 1?), on B are arranged to keep open air passages ZFig. 4 to the chamber C. The valve D has pin and slot or lost motionconnection 12 with the stem V.

In its initial position, as shown in Fig. 2, the valve body, B, is inthe condition of immersed equilibrium. The pressure in the chamber, C,surrounds it on all sides and its weight only rests upon the sprin K. Inthis position, also, the valve stem, T7, is held down on its seat, D bythe air pressure above it, which is not balanced on the diameter of D,beneath, an amount substantially equivalent to the air pressure on thediameter 3 of V plus the weight of the valve stem. \Vhen pressure entersthe chamber, C, it passes thru the passages 15 in the choke sleeve S,under the plunger, J, and causes it to rise carrying with it the sleeve,S, and the valve. body, B, on sprin K, until the valve body stopsagainst the piston V after which the continued upward movement of Jcompresses the spring, K, until C meets B and cuts off the air supply.At this point the additional lifting force of the spring, K, must beless than the load carried on the valve seat, 11, by a liberal margin,to insure a tightly closed exhaust as the plunger continues to rise bymomentum and lifts the valve stem, V at its seat, 11, away from thevalve face, D At this time the ports H are closed by the sleeve, S, andthe air within the valve stem immediately escapes reducing the pressurein the annular space above V to that of the exhaust, without affectingthe pressure beneath the plunger, J. The way is thus prepared for quickand positive action in the opening of the jarring cylinder to exhaust.The air trapped in the clearance space, Y, immediately expands liftingD, away from its seat 2 while air entering thru the choke holes, E,carries the valve stem up at apredetermined rate faster than the tablecan fall by gravity, but under control, to minimize the velocity ofimpact between the valve stem V and the cushion sleeve C. Hitherto inair thrown valves for a like purpose, the valve stem, V has struck thecap on the valve body above it at such high velocities as to be verydestructive. The cap bolts have frequently been broken and the valveparts have been upset in a way to prevent their proper action. Here thevelocity of the valve stem, V, is further reduced as V approaches B bythe increasing resistance of the outlets, X, for the air trapped aroundthem to which the normal leakage around the unpacked stem, Vcontributes. It may here be remarked that more or less leakage 1sunavoidable even when packing rings are employed and since some air willescape from the jarring cylinder in action when it should be confined, acorresponding input can do no harm. Good sliding fits without packingare therefore contemplated for the valve stem at V and V where thesleeve, S, covers the port holes H. In this way, also, full holding downpressure is assured 011 V after the ports, H, have been covered by thesleeve, S, on the rising stroke of the jarring plunger. Then, when thevalve stem seat, 11, is lifted from its face, D the air within the valvestem escapes to exhaust, and the valve stem rises picking up the exhaustvalve, D, and separating the face, D from its seat 2 for a wide openexhaust from the jarring cylinder, J. This upward movement of the valvestem is made as rapid as need be to exceed the downward velocity of thefalling plunger, slowing down toward the end of its travel to cushionthe impact between V and B \Vhen this contact has been made the valve,D, rests upon the cross pin, 12, and the face D is ad vanced by the lostmotion in the slot for the pin 12 to close the seat 2 before the plungerJ, strikes the plate 10 in the bottom of the jarring cylinder. hen thislost motion has been taken up, the valve face D closes against its seat11 and stops the downward movement of the valve stem and valve body,while the jarring plunger continues to fall opening a space between B,and C known as the valve lead, after which the body B is raised furtherby the spring, K, while air flows thru the choke holes, 15, to lift thearring plunger, J. In this way air is trapped in the jarring cylinderbefore the jarring blow is struck, thus saving in air consumption whilereducing the objectionable rebound, which tends to laminate the sand andprevent the uniform adhesion desired.

Further than this, the double seated valve, D, acts in effect like apilot to prepare the way for a wide open exhaust with the least possibleoverrun in the rising table beyond its position when exhaust begins.This is advantageous in plain machines because it makes substantialuniformity in length of stroke possible, and it is especially desirablein shockless machines where an overrun of the table tends to put thetable and anvil out of step with each other, causing the machine to runmore or less wild, striking blows at irregular intervals which vary inintensity and sometimes miss altogether as the table rides on air.V'Vhen the valve, D, steps against its seat, 2, and the plunger, J,continues to fall, the air trapped in the jarring cylinder will becompressed until D seats against 11, and begins to lift B away from C toadmit live air. The amount of this compression is determined by theclearance space when D is closed and the reduced space when the inletvalve opens, the difference being the volume represented by the plungerarea times the movement of D between its stops, which can be varied asdesired for different conditions. In general, however,

the pressure attained by compression should not exceed the minimum liveair pressure in the valve body, C, for which the spring, K, is adjusted.More compression will open the inlet valve, prematurely and lesscompresvalve thru which it passes to the tank, T, from which air isadmitted to the valve body, G, thru the admission or starting valve A. Gis a pressure gauge on the tank, T, by means of whichthe balancingpressure required to support the loaded table and the working pressurecan be observed. To read the pressure on the gauge G required to supportor balance the loaded table, the clamp for the spring 18 maybe releasedand air is admitted to the tank by partially opening the valve L, andjust as the table begins to rise the pressure on the gauge G is noted,atthe same time air enters the cylinder 22 and acts upon the piston 27which is slightly larger than the valve stem 25 beneath, thus the springcompressed and then the crosshead 19 1s-clamped in that position. Nowwhen the valve L is open wide the pressure in the tank will increase,say about 15%, and close the reducing valve towards its seat compressingthe spring 18. The gauge G now reads tie working pressure. As air isused in jarring, the valve .17 will automaticallyopen to mamtam tankpressure in excess of balancing; pressure. The latter must always exceedthe former by an amount required to give the desired speed which can beregulated by the reducing valve, R, in which the check valve 17 is heldopen by the'load spring 18 and closed by the tank pressure on the areaof its lower face. The

load spring, 18, acting upon the check valve,

17, carries at its upper end a crosshead, 19, adapted to slide on thestandards, 20, and be firmly secured thereto by the clamping bolt, 21.These standards are attached as shown to the reducing valve body, R, andcarry at their upper ends the cylinder, 22, in communication with thetank, T, thru the pipe 23. This cylinder is bored to a diameter, 26,slightly greater than the diameter,

25 of the valve stem, 17, and the crosshead, 19, is carried up into thecylinder, 22, to form the piston head, 27, in elastic connectiontherewith. The piston 27 is packed in its cylinder 22 and the pressurein the tank T, acts upon its area to compress the spring 18 when thestarting valve, A, is opened and air is admitted slowly thru the globevalve L, The

same pressure acts upon the check valve, 17, on its diameter, 25, whichis also packed in the valve body, R, but the area of 26 being greaterthan that of 25 and the weight of the movmg parts, acting in the samedirection, the pressure on 27 will overcome the opposing pressure on 17and hold the latter wide open. Under the above conditions the pressurein the tank T as indicated by the gauge G will be the balancing pressureon the plunger, J, requiredto support the jarring table and its load,whatever that may be, and if we now clamp the orosshead 19 to itsstandards, 20, we may follow this immediately by setting L wide open tooperate the machine. The pressure in the tank T will then rise automatically'to give a certain limiting speed asdesired for the loaded tableand the length of stroke will be kept within'the limit required forshockless machines to keep the table and anvil in step- 28 is a flexiblehose connection between the starting valve, A, and the jarring table,and 24 1s a drip cock for drawing oii the water of condensation in thetank,

T,'but of course the outlet to the machine can be arranged as desired tocarry off all liquid deposits thru the exhaust from the jarringcylinder.

As shown in Fig. 2 the jarring plunger is at rest above its strikingplate, 10, supported by the cushion, 9, and the plate, 8, be-

neath, the admission valve, B, has been raised from its seat C by thevalve stem V and carried up to wide open position by the expansion ofthe spring, K. g

It has been observed that the valve stem V in rising, under thepressureadmitted thru the choke holes, E, will be stopped and held from afurther upward movement by the bushing B and it should be pointed outthat this follows from the relative areas nested and opposed to eachother in sliding relation. Some latitude is permissible in theserelative areas but not a great deal, and,

to illustrate suitable proportions, care has been taken to make thedescriptive numbers applied to the several diameters, proportional tothe actual-diameters required, beginning with 3 for the diameter of Vand ending .with 7, for the diameter of the valve 13,.

In the drawing the parts are shown in the positions which they occupywhen the air is turned off from the inlet, I, at some point outside ofthe machine, as at A or the valve L.

' The operation may be recapitulated as fol lows:

When air under pressure is turned on to lift the plunger, J,'it passesthe choke holes 15 in the sleeve, S, entering the jarring cy1- inder, 1,below the plunger J, lifting the plunger and table, and the area of theholes, 15, limits the speed of the plunger and table. The reducingvalve, R, performs a similar function with respect to the load on thetable. If the load on the table is comparatively light,

the valve, R, may be assumed to remain in the position shown in Fig. 1with its spring, 18, but little compressed, but if the load iscomparatively heavy, the pressure under the plunger required to lift it,as shown by the gauge, G, and the spring, 18, is adjusted automaticallyand the crosshead, 19, is clamped in the position assumed, thusincreasing the pressure in the tank, T, and adjusting the air supply tothe load. In this way an abundant supply of air at proper workingpressure can be held near the machine to meet any require ments and atlittle or no expense, because the air tank, T, now serves as a valvestand and the reducing valve, R, is a very simple and cheap device toaccomplish the end in view.

Air under pressure enters not only the jarring cylinder, 1, and liftsthe plunger, J, but also enters the chamber in the stem, V, by way of,H, and passes thru the ports, X, into the annular space over V Theadmission valve, B is held open by the spring IQ In rising, the plungerlifts the sleeve, S, covering ports, H, thus excluding the interior ofstem, V, from the ingress of air under pressure. The pressure in thestem, V, acting thru the holes, X, upon the piston head of the valvestem, serves with the direct pressure on V to hold down the exhaustvalve D. As the plunger rises the stem V remains stationary and theadmission valve seat, 0 contacts with the valve face, B closing airadmission, thereupon thru the lost motion connection the port, 11, isuncovered and the interior of the stem, V, connected to exhaust as isalso the space over V The result of this is that air trapped in Y aswell as air entering through holes E throws the stem upward with a quickmotion at first and slower motion thereafter due to the restricted areaof the holes, E, and this upward motion of the stem, V, opens theexhaust wide and quickly. The valve stem, V, is cushioned in its upwardmovement by the reduced outlets, X, before contact takes place between Vand B and as the plunger now falls, the lost motion connection 12 causesthe valve, D, to close the exhaust and to trap air under the plunger sothat the fall of the plunger is checked, thus insuring that the mold orflask, which is falling with the table, is in good contact with it whenthe blow is struck. A short distance before impact occurs, the valvestem at V meets the bushing B and stops the valve face B while the valveseat C continues to move, thus opening the jarring cylinder to liveairfollowed by a wider admission. The parts thus assume the position shownin F ig. 1, the spring, K, having lifted the body, B, and opened theadmission valve for a repetition of the described jarring operation. Thejarring action may be stopped and started by means of the valve, A,alone, until a different load on the table requires a readjustment ofthe reducing valve, R.

It will be obvious to those skilled in the art to which the inventionrelates that modifications may be made in details of construction andarrangement and in matters of mere form without departing from thespirit of the invention which is not limited to such matters orotherwise than the prior art and the appended claims may requirez Iclaim:

1. In a ar ramming molding machine having a cylinder and a hollowplunger and a source of air supply under pressure and an exhaust portfor the cylinder, and in combination a tubular air chamber and a sleevefixed in spaced relation to the plunger to provide an air inlet passageto the cylinder, a tubular valve body spaced from the inner wall of thechamber to provide a continuation of said inlet passage, a springinterposed between the sleeve and body to support the weight of thelatter, a hollow valve spindle mounted in the body and having one endclosed and exposed through the top of the body and having near the otherendan exhaust port, a two faced exhaust valve carried by and having lostmotion in respect to the spindle and having one face for cooperationwith the spindle exhaust port and the other face for cooperation withthe cylinder exhaust port, admission valve elements pro vided betweenthe air chamber and the body and which also operate to raise the body bythe plunger, air admission ports arranged below the admission valveelements and in position for cooperation with the sleeve and extendingfrom the inlet passage to the interior of the spindle, a piston elementprovided on the spindle, cylinder spaces pr0- vided in thebody above andbelow the piston element and of which the lower one is pro vided with ahead adaptedto lift the spindle element by the piston element and awayfrom the seated exhaust valve as the body is moved by the moving chamberand plunger, and ports provided from the lower cylinder space to the airinlet passage and ports provided from the upper cylinder space to theinterior of the spindle whereby when the spindle uncovers the seatedexhaust valve by the lifting action of the chamber and body and plungerthe spindle is moved by its piston under the differential air pressurein the cylinder spaces and quickly lifts the exhaust valve to uncoverthe cylinder exhaust port.

2. In a jar ramming molding machine having a cylinder and a hollowplunger and a source of air suply under pressure and an exhaust port forthe cylinder and in combination a tubular air chamber having anadmission valve element and carried by the plunger, a spring supportedtubular valve body within the chamber and having an admission valveelement, a hollow valve spin-- dle having an exhaust port, a two facedexhaust valve carried by and having lost motion in respect to thespindle and of which one face cooperates with the cylinder exhaust portand of which the other face cooperates with the spindle exhaust port,pneumatic means for holding the spindle down onto the exhaust valve andthe exhaust valve down onto the cylinder exhaust port as the risingplunger and chamber close the admission valve and for then lifting thespindle to uncover its exhaust port by means provided between the bodyand spindle, and pneumatic provisions operative in respect to theopening of the spindle exhaust port to rapidly raise the spindle andwith it the exhaust valve to uncover the cylinder exhaust port.

3. I11 a jar ramming molding machine hav ing a cylinder and a hollowplunger and a a source of air supply under pressure and an exhaust portfor the cylinder, and in combination an air admission valve elementclosed by rising movement of the plunger, a double faced exhaust valveof which one face covers the cylinder exhaust port, pneumatic mechanismfor holding the exhaust valve in position to cover the cylinder exhaustport during part of the rising motion of the plunger, and pneumaticmeans having an exhaust port controlled by the other face of the exhaustvalve and adapted for mechanical actuation by further rising movement ofthe plunger to uncover the last mentioned exhaust port and to thereafterlift the exhaust valve with a quick mot-ion to uncover the cylinderexhaust.

4. In a ramming molding machine having a. cylinder and a hollow plungerand a source of air supply under pressure and an exhaust port for thecylinder, and in combination an exhaust valve covering the cylinderexhaust port, pneumatic means for holding the exhaust valve in positionfor covering said port during a part of the rising movement of theplunger, and pneumatic means controlled by the rising motion of theplunger and adapted to move said exhaust valve quickly to uncover thecylinder exhaust during a continuation of the movement of the plunger.

5. In a jar ramming molding machine a plunger and cylinder, a pneumaticpower device, admission and exhaust valves for the cylinder and for thepneumatic power device, means operated by upward movement of the plungerfor closing the admission valve of the cylinder and the admission valveof the power device, means for mechanically opening the exhaust valve ofthe power device by further upward movement of the plunger, andconnections between the exhaust valve of the cylinder and the powerdevice whereby when the power device exhaust valve is Opened said deviceoperates pneumatically to rapidly open the cylinder exhaust valve.

WILFRED LEWIS.

